Currently, pressure regulators are known in the art for use with sprinklers where the source water pressure may vary or otherwise be excessive for the sprinkler. Under ideal operating conditions, the internal pressure due to water flow would be relatively constant or at least within a specified, limited range. If the internal pressure exceeds the specified range, the sprinkler will not distribute water in a desirable manner. For instance, the water may be emitted at an excessive distance or force, and the desired coverage area will not be properly watered. Alternatively, a spinning-type sprinkler, having a head portion rotated by the force of the water flow, may spin too rapidly. In such a case, the emitted water stream or streams will not have time to develop the proper emission profile, instead “tailing” and being emitted a shorter distance than desired.
In simple terms, a pressure regulator is a mechanism having a portion or member that shifts positions depending on water pressure so that the water flow through the sprinkler remains within a desired range as the water pressure varies. A pressure regulator typically utilizes a pressure responsive moveable flow member that shifts within the water flow to regulate the size of a passageway around or through the moveable member and a stationary structure such as a pressure regulator valve seat. If the water pressure is excessive, the moveable member is shifted against the spring bias towards the structure so that the passage between the moveable member and the stationary structure is decreased in size. At ideal pressure, or below, the moveable member is biased by the spring away from the structure so as to maximize the size of the passage therebetween and to minimize the pressure drop across the interface between the moveable member and the valve seat.
In many cases, the moveable member is biased open and away from the valve seat. In some applications, the moveable member is biased towards the outlet or nozzle of the sprinkler and has a first face, downwardly directed into an incoming water stream, and a second face upwardly directed towards a cavity into which the water flows. As the water fills the cavity under pressure, the water exerts a pressure against both the first and second faces. By providing a larger surface area on the upwardly-facing second face than on the downwardly facing first face, the pressure acting downwardly on the moveable member is greater than the force acting upwardly. If there is a sufficient force differential between the faces, the spring bias is overcome and the moveable member is forced downward and towards the valve seat. The pressure regulator thereby acts to decrease the passageway between the moveable member and valve seat for the water, which consequently decreases the water flow and increases the pressure drop therethrough.
These types of pressure regulators are located in the flow of the water. As the water flows through the source pipe and through each component of the sprinkler itself, such as the inlet or pipe junctures, there is a pressure or head loss. If not located in close proximity to the sprinkler, the pressure regulator is subject to pressures which are not the same as those that would be experienced by the sprinkler head itself. It is therefore desirable for the pressure regulator to be closely located to the components of the sprinkler whose operation is effected by the water pressure.
A pop-up type sprinkler includes a case housing that connects to a source pipe for delivering water to the sprinkler. Within the case housing, a moving or moveable housing is located. The moveable housing is spring-biased to a retracted position so that it is located within the case when the sprinkler is not operating. When the sprinkler is activated, water is delivered to the sprinkler so that a water stream applies pressure to the moveable housing, thereby overcoming the spring bias and forcing the housing upward to a position extended from the case. The water continues through the moveable housing and is emitted by a sprinkler nozzle or outlet.
The pop-up sprinkler has a size which is dependent on the application and often includes a mechanism for allowing a sprinkler head portion of the moveable housing to rotate. For instance, a spinning-type sprinkler has a spinning deflector plate located above openings in the moveable housing through which water passes. The water strikes vanes of the deflector plate to cause the water to be distributed radially therefrom and to drive the deflector plate in a rotational manner. This type of sprinkler has a relatively small head portion.
In other cases, the moveable housing includes a drive train for converting the kinetic energy and force into rotational torque for controllably rotating the head portion of the moveable housing. The water is then emitted from the rotating head portion. Although some sprinklers have a speed control mechanism, in many types of sprinklers it is the pressure and flow rate of the water stream that are responsible for the rotation rate of the head portion. In use, control of the water flow through the drive train by a pressure regulator benefits from the pressure regulator being positioned upstream from the drive train.
Use of a conventional pressure regulator with a drive train can significantly increases the size, and in particular the length, of the moveable housing. The larger moveable housing may also requires a larger stem housing into which the moveable housing may retract. These factors contribute to an increase in cost and installation requirements.
In other applications, the pressure regulator may be located in the source pipe or upstream from a sprinkler head of any type. As described, the pressure regulator design utilizes a spring, which often requires a cavity within which the spring is located. This design benefits from the cavity being generally sealed from the pressurized water flow. If pressurized water is allowed to enter, the described pressure-differential is reduced or eliminated. However, the shifting of the moveable member causes the size of the cavity to be compressed and expanded. Therefore, the cavity is preferably vented to an ambient or reference pressure, such as the atmospheric environment.
Providing a vent can be problematic because the vent often provides a path for dirt and grit to enter the atmospheric or referential pressure cavity. Such entry may cause problems with the shifting of the moveable member, the moving of the spring, and the sealing between the moveable member and a support structure.
Accordingly, there has been a need for an improved pressure regulator, and a pressure regulator for use in compact constructions.